Pre-implantation genetic diagnosis-should we use ICSI for all?

objectiveIntracytoplasmic sperm injection (ICSI) is commonly used during pre-implantation genetic diagnosis (PGD) in vitro fertilization (IVF), aiming to eliminate the risk of contamination from extraneous sperm DNA. Recently, ICSI "overuse" in non-male infertility has been doubted, since it does not offer an advantage over IVF. Prompted by the aforementioned observations, we sought to assess the accuracy of IVF vs ICSI in PGD cases, as might be reflected by a difference in the prevalence of discarded embryos as a consequent of parental contamination.

methodsCohort-historical study of all consecutive patients admitted to the IVF-PGD program in a large tertiary center. The percentages of complete, incomplete diagnosis, PCR failure, abnormal embryos, and the contamination rate with paternal DNA in the IVF-only and the ICSI-only groups. We reviewed the computerized files of all consecutive women admitted to our IVF for a PGD-PCR cycle. Patients were divided accordingly into three groups: an IVF group-where all the oocytes underwent IVF only, an ICSI group-where all oocytes underwent ICSI, and a mixed group-where sibling oocytes underwent both IVF and ICSI. The laboratory data and the genetic diagnostic results were collected and compared between the different insemination groups.

resultsNine-hundred and twenty-seven patients underwent IVF-PGD cycles in our program, 315 in the IVF group, 565 in the ICSI group, and 47 in the mixed group. No differences were observed in fertilization rates, the percentage of embryos available for biopsy, and the percentages of complete, incomplete diagnosis, PCR failure, or abnormal embryos, between the IVF-only and the ICSI-only groups and between the IVF and the ICSI of sibling oocytes in the mixed group. Moreover, contamination with paternal DNA, through contamination with sperm cells, was negligible. Not one single case of misdiagnosis was encountered during the study period.

conclusionIt might be therefore concluded that IVF should be the preferred insemination methods in PGD cycles, and ICSI should be indicated only in cases of male-factor infertility.